There are two populations in which the prevalence of Human Immunodeficiency Virus infection and AIDS increasing: intravenous drug users and their children. Screening of pregnant women with a history of intravenous drug use at the University of Maryland has revealed a thirty percent seropositivity rate, yet the drug using community does not recognize AIDS as the major threat to their health, nor to the health of their children. The unprocedented social and economic impact of the emergence of these two populations will be felt by the entire society. Effective prevention efforts are desperately needed. The major obstacle to the prevention of HIV infection is the lack of understanding of factors contributing to the transmission of HIV and to the development of clinical disease. This protocol will provide the definitive assessment of: 1) the effect of HIV infection on pregnancy outcome, 2) factors affecting the rate of transmission from mother to child, 3) the development of disease in both the maternal and pediatric populations and 4) the impact of HIV infection and childbirth upon drug use behavior. Obstetric patients with a history of intravenous drug use will be screened for HIV antibody profile, immunologic assessment, HIV culture and an assessment of current drug usage and addiction severity. At delivery, the cord blood of the infant will also be screened for immunologic function. HIV antibody profile, culture and for detection of fetal lgM synthesis. The children will be followed for the development of antibody response to HIV, immunologic dysfunction and clinical disease. Followup of the maternal population shall include repeat immunologic and virologic assessments and comparison of drug use before and after identification of HIV positivity or child birth. The application of Western Blot technology will outcome analysis with respect to immunologic response to HIV infection. This information will provide the basis for counseling the drug using population regarding their risk, particularly during pregnancy, of HIV infection. That this information may provide the impetus for risk reduction behavior and decreased spread of the agent will be assessed. These results will also enable the anticipation of risk in the pediatric population for the development of disease. Early identification will permit early intervention in order to reduce the morbidity and mortality associated with HIV infection.